Main risks and Vulnerability of Population in the World and Mexico.

 

Hydrometeorologic, Gelologic, Chemical and Sanitary Risks in the World and Mexico.

 

Population is exposed to a large range of natural processes or anthropic actions (caused by humankind).

A risk implies the presence of a factor or event of diverse origin:

 

* Underground fractures or faults

* Possible landslides or flooding zones

* High seismicity zones

* Closeness to chemical or gas industries

 

The risk is higher when there are great  people settlements close to active volcanoes, in zones of high seismicity or hurricane impact zones and also if there is no adequate organization for disaster prevention.

 

Risks can be classified like this:

 

Process		Examples
Natural	Geological	Earthquakes, volcanic eruption, erosion, collapses , seaquakes, sinking.
	Hydrometeorological	Hurricanes, tornados, dust storms, flooding, hailstorms, frost, draughts, tropical storms.
Anthropic	Chemical-technological	Fires, explosions, gas leaks, petroleum and toxic substances spills (liquid or gas kinds),  dangerous waste.
	Sanitary-ecological	Water ,soil, air, food pollution: Epidemies  and plagues.
	Socio-organizational	In massive concentrations: terrestrial, flying, sailing and rain accidents. Public  services interruption.

 

The extension of space where the disaster occurs varies in order to the strength and length of the event.  Since 2011, the amounts of disasters kept showing the impact that natural disasters have in human health and society.

 

A disaster is called so when the following two circumstances appear:

 

* Violent emergence of a high destructive power phenomenon that affects a region or zone.

* The existence of a community vulnerable to its impact.

 

Vulnerability is how susceptible a population is to suffer damage. Population that live in rural zones is more vulnerable  because it would be harder for them to rebuild their houses and recover their agriculture products or livestock.

 

A disaster can also provoke epidemics, scarcity of food and losing jobs. Recovery may be faster and easier in urban zones. In central cities they are more vulnerable to terrorist attacks and anthropic risks.

 

Poor populations, because of their lack of money sometimes establish themselves in high risk zones, like seismic, volcanic, close to tectonic faults or affected by hurricanes and flooding and in housing built with inappropriate techniques and materials. (Like a house built with cardboard and metal sheets.

 

 

 

Other factors that incide vulnerability are:

 

* Inefficiency of public services

* Lack of education on disaster prevention

* Not enough infrastructure to help all the population in case of disaster

* Passive attitude of the population

 

A disaster happens when two factors combine: Risk and vulnerability.

 

Risk + Vulnerability = Disaster

 

The study of disasters social impact is very important. The main indicators are:

 

* Number of people death and hurt

* Amount of victims of damage

* Housing and work  buildings damage

 

Population is more vulnerable to unpredictable phenomena like earthquakes, which cause huge damage to life and material goods. Predictable phenomenon gives some time to be prepared and take security measures (like cyclones) in which damages are less.

 

The areas with higher frequency and strength of hydrometeorological phenomena are the places with lots of rain and cyclones. There rivers overflow, flooding, landslide, lose of soil, beaches sand, agriculture products, livestock and housing happen  in them.

 

Other big disasters are caused by technologic origin like toxic substances spill (PETROLEUM), fires, nuclear accidents, air, water and soil pollution as well. Other dangers of anthropologic origin are wars that favour epidemics, famine (people in hunger conditions) and environment destruction.

 

http://www.volcanodiscovery.com/faq/how_dangerous_are_volcanoes.html

Mount Vesuvius

Vesuvius has 4 typical types of eruptions:
1. Plinian (such as the 79 AD Pompeii eruption): extremely large explosive eruptions producing several to several tens of cubic km of magma in a very short time.
2. Sub-Plinian explosive eruptions (such as the 1631 eruption). They are similar in style, but smaller than true Plinian events.
3. Strombolian and Vulcanian eruptions (several examples during the 1631-1944 period, e.g. 1906 and 1944). Such eruptions produce local heavy tephra falls, small pyroclastic flows, as well as large fire fountains and lava flows.
4. The smallest, but most frequent type of activity observed at Vesuvius is persistent Strombolian to Hawaiian-style activity that prevailed during much of the period between 1631 and 1944. This activity is usually limited to the central crater, and sometimes to flank vents. Lava flows and lava fountains have been frequently observed during such periods of activity.
Eruptions of  1796 - 1822, 1824 - 1834, 1835 - 1839, 1841 - 16 February 1850, 1854 - 1855, 1855 - 1861, 1864 - 1868, 1870 - 1872, 1875 - 1906, 1913 - 4 April 1944

Krakatoa - the world's most infamous volcano

The island group of Krakatoa (or Krakatau) lies in the Sunda Strait between Java and Sumatra. Krakatoa is infamous for its violent Plinian eruption in 1883, that destroyed the previous volcanic edifice and enlarged its caldera.
Collapse of the former volcanic edifice, perhaps in 416 AD, had formed a 7-km-wide caldera. Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan and Perbuwatan volcanoes were formed, coalescing to create the pre-1883 Krakatoa island. Caldera collapse during the catastrophic 1883 eruption destroyed Danan and Perbuwatan volcanoes, and left only a remnant of Rakata volcano.
This eruption, the 2nd largest in Indonesia during historical time (the most violent being the eruption of Tambora in 1815), caused more than 36,000 fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java. Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatoa ("Child of Krakatoa") was constructed within the 1883 caldera at a point between the former cones of Danan and Perbuwatan. Anak Krakatau has been the site of frequent eruptions since 1927.

 

Typical eruption style: unspecified
Pelée volcano eruptions: 1932
Last earthquakes nearby:

Time

Mag. / Depth

Distance

LocationNo recent earthquakes

Background:

Renowned Montagne Pelée, forming the northern end of the island of Martinique, is the most active volcano of the Lesser Antilles arc. Three major edifice failures since the late Pleistocene, the last about 9000 years ago, have left large horseshoe-shaped calderas breached to the SW inside which the modern volcano has been constructed. More than 20 major eruptions have occurred at Pelée during the past 5000 years. Extensive pyroclastic-flow deposits, incised by steep-walled ravines, mantle the slopes of the volcano. The l'Etang Sec summit crater is filled by two lava domes emplaced during the 1902 and 1929 eruptions. Historical eruptions date back to the 18th century; only two modest phreatic or phreatomagmatic eruptions took place prior to 1902. The catastrophic 1902 eruption, which destroyed the city of St. Pierre, the "Pearl of the Lesser Antilles," became the type-example of pelean eruptions and marked the onset of modern volcanological studies of the behavior of pyroclastic flows.

 

Popocatépetl volcano

Stratovolcano 5426 m / 17,802 ft
Central Mexico, 19.02°N / -98.62°W
Current status: erupting (4 out of 5)
Popocatépetl webcams / live data

[show map]

Last update: 8 May 2013 (steam and ash emissions, intermittent explosions)
Typical eruption style: Dominantly explosive, construction of lava domes. Plinian eruptions at intervals of several centuries or few thousands of years, vulcanian and strombolian activity in intermittent phases.

 

 

 

Popocatépetl volcano eruptions: 1345-47, 1354, 1363(?), 1488, 1504, 1509(?), 1512, 1518, 1519-23(?), 1528, 1530, 1539-40, 1542, 1548, 1571, 1580, 1590, 1592-94, 1642, 1663-65, 1666-67, 1697, 1720, 1802-04, 1827(?), 1834(?), 1852(?), 1919-22, 1923-24, 1925-27(?), 1933, 1942-43, 1947, 1994-95, 1996-2003, 2004-ongoing

Last earthquakes nearby:

Time	Mag. / Depth	Distance	Location
Mon, 6 May
Mon, 6 May 08:33 UTC	M 3.4 / 3 km	2 km	19 km al ESTE de OZUMBA, MEX
Tue, 30 Apr
Tue, 30 Apr 16:09 UTC	M 3.2 / 3 km	24 km	2 km al NOROESTE de S ANDRES MIXQUIC, DF

Popocatepetl is one of Mexico's most active volcanoes. After almost 50 years of dormancy, "Popo" came back to life in 1994 and has since then been producing powerful explosions at irregular intervals.
In the past centuries before European invasions, large eruptions produced giant mud flows that have buried Atztec settlements, even entire pyramids.

Background:

Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 250-450 m deep crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano.
At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas south of the volcano. The modern volcano was constructed to the south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 AD, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since precolumbian time.

 

Environment Degradation and Natural Disasters in the World and Mexico

 

Natural events like earthquakes, hurricanes and tsunamis cause bigger disaster because their intensity and frequency.

Geologic risks, volcanic eruptions and earthquakes cause great environmental damage. Fires are another kind of risks that impact on the environment because they destroy woods, biodiversity and grassland.

 

Social disasters produce great lost (explosions, toxic substances spills, epidemics) that affect the environment and population.

 

A disaster causes direct and indirect loss. Direct are immediately evident (death, destruction of infrastructure, cultural and private patrimony, etc. Indirect are the social and economic consequences as people relocation, sicknesses and epidemics, ack of food and housing destruction.

 

Economic activity is affected when stores  and services buildings are destroyed, there is jobs , touristic commercial and industrial loss.

 

Because of its geographic position Mexico is exposed to different kind of geologic and hydrometeorologic disasters. More than one third of Mexican population lives in high risk zonesnmainly in Guerrero, Oaxaca and Chiapas because of preassure of ocean plates of the Pacific, Cocos and Northamerican that produce igh volcanic activity.

 

Mexico is also a zone of hidrometeorological risk because hurricane impact and is vulnerable to suffer floodings because of its flowing rivers.

 

The majority of a disaster effects are caused by hurricanes that  are strong at the coasts of Mexico specially the south and southeast of the country, in contrast with the north states like Coahuila, Durango and San Luis Potosi that are vulnerable to disasters caused by droughts.

 

A thyphoon is a cyclone  originated in the west Pacific  and Indic Ocean (Japan, China).

 

Social damage is higher if there isn’t an adequate organization of the authorities and society to have shelter, medicine, medical help, food and all the necessary support of an affected population.

 

To decrease population vulnerability and risk it is very important to spread prevention culture and education, people must be organized trained in emergency situations and work together with the prevention steps with authorities in charge.

 

Two thirds of the country are in seismic risk because to Cocos and Northamerican subduction  plates.  Being located at the Pacific Fire Ring in Mexico there are a great number of volcanoes: Colima, Popocatépetl, Ceboruco, Tacaná and Chinchón.

 

Mexico is located in a inter-tropical region and that’s why each year there are around 20 cyclones, 4 or 5 of which  get into our territory and cause big damage  like flooding and landslides at Pacific and Gulf of Mexico and Caribbean coasts.